Effects of ONO-1078, a peptide leukotriene antagonist, on endotoxin- induced acute lung injury

The role of lipoxygenase metabolites in the pathogenesis of endotoxin (LPS)-induced lung injury remains to be clarified. We investigated the contribution of peptide leukotrienes to LPS-induced acute lung injury using a potent antagonist, ONO-1078 (ONO). Experimental groups consisted of a saline group (n = 10), an LPS group (n = 9) injected intravenously with 2 mg E. coli LPS, an ONO group (n = 8) receiving 30 mg/kg of intraperitoneal ONO, and an LPS + ONO group (n = 6) receiving 30 mg/kg of ONO intraperitoneally 10 min before the LPS injection. The [¹²⁵I]albumin lung plasma ratio, which is a parameter of acute lung injury, was significantly increased (p < 0.01) in the LPS group compared with the saline, ONO, and LPS + ONO groups. The [¹²⁵I]albumin BAL fluid plasma ratio was also increased (p < 0.01) in the LPS group compared with the other groups. ONO pretreatment attenuated the LPS-induced increases in neutrophil counts in the BAL fluid. In vitro studies showed that ONO suppresses the neutrophil chemotaxis induced by LTB₄, zymosan-activated serum, and FMLP. We conclude that (1) ONO-1078 attenuates LPS-induced acute lung injury; and (2) this effect appears mainly a result of its potent antagonistic actions against peptide leukotrienes and also, in part, the suppression of neutrophil chemotaxis.